These mobs are definitely BLMs. Unless silenced, they like to spam Sleepga and any -ga spells you can think of.
They appear in Al Zahbi during Besieged, Wajaom Woodlands ( near the entrances to Mamook ) and in Bhaflau Thickets ( near the Mamool Ja staging point ), and they're decent for exp from 72-75. Just make sure you have a Silence/Stun in the party, because these things can take you down quick if they're allowed to cast.
These things also look very much like the Mamool Ja Hospitalers which appear during Besieged. The Hospitalers, though, are WHMs.